<!doctype html>
<html>
  <head>
    <title>MathML fallback</title>
    <meta charset="utf-8"/>
    <style type="text/css">
      span.mathblock {
        display: block;
        text-align: center;
      }
      span.annotation {
        display: inline-block;
      }
    </style>
  </head>
  <body>

    <p>
      <span>
        <span>
          <span>2</span>
          <span>x</span>
        </span>
      </span>
      <span class="mathblock">
        <span>
          <span>2</span>
          <span>x</span>
        </span>
      </span>
    </p>

    <p>
      <span>
        <span>
          <span class="annotation">\frac{2}{x}</span>
        </span>
      </span>
      <span class="mathblock">
        <span>
          <span class="annotation">\frac{2}{x}</span>
        </span>
      </span>
    </p>

    <p>
      <span>
        <span>
          <span class="annotation"><span><img src="" alt="2/x"/></span></span>
        </span>
      </span>
      <span class="mathblock">
        <span>
          <span class="annotation"><span><img src="" alt="2/x"/></span></span>
        </span>
      </span>
    </p>

  </body>
</html>
